Move mojo/public/c/gpu/* to mojo/public/c/include.

examples/shadows/vfx/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 config("glm") {
   include_dirs = [ "//third_party/glm" ]
 }
 
 source_set("vfx") {
   sources = [
     "color_program.cc",
     "color_program.h",
     "element_array_buffer.h",
     "program.cc",
     "program.h",
     "shader.cc",
     "shader.h",
   ]
 
   public_configs = [ ":glm" ]
 
   deps = [
     "//base",
-    "//mojo/public/c/gpu",
+    "//mojo/public/c:gpu",
   ]
 }